Background Right heart catheterization (RHC) is a high-risk procedure in children with pulmonary arterial hypertension without clear guidelines for the indications and targets of invasive reassessment. Our objectives are to define the aims of repeated RHC and evaluate the correlation between noninvasive criteria and hemodynamic parameters. Methods and Results Clinical and hemodynamic characteristics from 71 incident treatment-naïve children (median age 6.2 years) with pulmonary arterial hypertension who had a baseline and reevaluation RHC were analyzed. Correlations between noninvasive predictors and hemodynamic parameters were tested. Adverse outcomes were defined as death, lung transplantation, or Potts shunt. At baseline, pulmonary vascular resistance index (hazard ratio [HR] 1.07 per 1 WU·m2 increase [95% CI, 1.02-1.12], P=0.002), stroke volume index (HR 0.95 per 1 L·min-1·m-2 increase [95% CI, 0.91-0.99], P=0.012), pulmonary artery compliance index (HR 0.16 per 1 mL·mm Hg-1·m-2 increase [95% CI, 0.051-0.52], P=0.002), and right atrial pressure (HR, 1.31 per 1 mm Hg increase [95% CI, 1.01-1.71], P=0.043) were associated with adverse outcomes. Pulmonary vascular resistance index, pulmonary artery compliance index, and right atrial pressure were still associated with a worse outcome at second RHC. Noninvasive criteria accurately predicted hemodynamic evolution; however, 70% of the patients who had improved based on noninvasive criteria still presented at least 1 "at risk" hemodynamics at second RHC. Conclusions Pulmonary vascular resistance index, pulmonary artery compliance index, and right atrial pressure are solid predictors of adverse outcomes in pediatric pulmonary arterial hypertension and potential therapeutic targets. Noninvasive criteria accurately predict the evolution of hemodynamic parameters, but insufficiently. Repeated RHC are helpful to identify children with persistent higher risk after treatment introduction.